Transformer



V. M. MONTSINGER- TRANSFORMER Filed Oct; 25', 1927 Inventor: Vincent M. Mont'sin y M H is Attorney.

Patented July 17, 1928.

UNITED STATES 1,677,681 PATENT. OFFICE.

VINCENT M. MONTSINGER, OF PITTSFIELID, IVIASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TRANSFORMER.

Application filed October 25, 1927.

My invention relates to transformers and more particularly to transformers of the horizontal core type which are immersed in an insulating and cooling liquid such as oil. In a transformer of the horizontal core type, the core comprises a horizontal winding leg surrounded by the transformer windings. It is customary to provide a cylinder of insulating material surrounding the winding leg and interposed between that leg and the windings for the purpose of supporting the windings and insulating them from the winding leg. This construction is particularly applicable where the windings are formed of spaced disk coils of considerable radial width because the winding coils are in vertical positions and any cooling medium such as insulating oil in which the trans former may be immersed will flow by convection through the vertical spaces between the coils and cool the coils efficiently. The cooling of the horizontal winding leg of the core has not been so satisfactory heretofore, however, because the horizontal position of any cooling ducts in the winding leg or between it and the surrounding insulating cylinder has resulted in little tendency for convection currents of the cooling liquid to flow through them. The general object of the present invention is to provide an improved arrangement of horizontal core type transformer in which not only the windings but also the winding leg of the core will be efficiently cooled.

The invention will be better understood from the following description taken in connection with the accompanying drawing in which Fig. 1 is a View, partly in section, of a transformer of the horizontal core type arranged in acrordance with the invention and Fig. 2 is a sectional view on the line 2-2 of Fig. 1.

Like reference characters indicate similar parts in both figures of the drawing.

The transformer shown in the drawing is of the horizontal core type and comprises a magnetic core 10 having a winding leg 11 which is disposed in a generally horizontal position. The winding leg 11 is surrounded by a cylinder 12 of suitable insulating material and this in turn supports and is surrounded by the transformer windings 13 which are of the disk coil type. The winding leg 11 is formed in two spaced sections to provide an internal longitudinal Serial No. 228,644.

space 14 which is sometimes desirable in the larger sizes of transformer for efficient cooling ofthe interior of the winding leg by the cooling liquid 15 in which the transformer is immersed. The winding leg 11 is built up of laminations of different widths so that its form is difierent from that of the opening in the surrounding insulating cylinder 12. This results in longitudinal ventilating spaces 16 between the winding leg and cylinder through which the liquid 15 may flow to cool the winding leg.

The hysteresis and eddy current losses in the winding leg 11 of the core appear as heat which is transmitted to the liquid in the spaces or ducts 14; and 16 and it is necessary that a circulation of liquid be maintained in these ducts to cool the winding leg. With the winding leg and duct-s disposed in a horizontal position, however, as has been the general practice heretofore in transformers of the horizontal core type. there is little tendency for the heated liquid in the ducts to rise by convection and be replaced, by cooler liquid from below. In connection with the present invention, however, it was discovered that an unexpectedly slight longitudinal inclination from an exactly horizontal position of the winding leg and the ducts extending along its surface would increase the convection currents of liquid through the ducts to such an extent as to cause a decided decrease in the temperature of the winding leg. In a particular transformer constructed and arranged substantially as shown in the drawing, it has been found, for example, that by changing the position of the winding leg from horizontal to an inclination of only approximately two degrees from horizontal, all other conditions remaining unchanged, the temperatures of the most heated parts of the winding leg were reduced nearly fifteen degrees centigrade, the greatest reduction actually measured being 14.9 centigrade. A further inclination of the winding leg to an angle of approximately four degrees from horizontal produced an additional reduction in the temperatures of its most heated parts of between five and six degrees centigrade. A still further inclination of the winding leg to an angle of approximately eight degrees from horizontal produced a still further reduction in these temperatures of between six and seven degrees Centigrade.

These effects of tipping or inclining the Winding leg slightly from a horizontal position would probably vary somewhat in transformers of different sizes and proportions of parts but they show the decided advantage which is secured by small inclinations of the winding leg. It is desirable, of course, that the complete core and windings of the transformer be inc-lined with the winding leg in order not to distort the openings in'the core through which the windings pass. It is not desirable, however, that the casing 17 and particularly its base portion 18 be inclined or tipped, it being considered preferable to incline the winding leg or the complete core and windings at the desired small angle with respect to the casing. With this arrangement, the transformer with its casing may be supported on the usual level foundation and the walls of the casing will have the proper vertical position to present a good appearance. The weight will also be well distributed on the foundation.

The invention has been explained in connection with a particular horizontal core type transformer but it will be apparent that various changes in. the arrangement and proportion of the parts of the transformer may be made within the scope of the invention as defined in the appended claims.

WVhat I claim as new and desire to secure by Letters Patent of the United States is:

1. A transformer of the horizontal core type immersed'in a cooling liquid within a surrounding casing, said transformer including 'a magnetic core having a winding leg, an insulating cylinder surounding said winding leg, there being longitudinal space along the surface of said winding leg within said cylinder, and windings surrounding said cylinder, said winding leg and cylinder being longitudinally inclined at a. small angle from horizontal.

2. A tranxrormer of the horizontal cortype immersed in a cooling liquid within a surrounding casing, said transformer in cluding a magnetic core having a winding leg, an insulating cylinder surrounding said winding leg, there being longitudinal space along the surface of said winding leg within said cylinder, and windin s surround ing said cylinder, said winding leg and cylinder being longitudinally inclined at a small angle with respect to the base of said casing.

3. A transformer of the horizontal core type immersedin a cooling liquid within a surrounding casing, said transformer in cluding a magnetic core having a winding leg, an insulating cylinder surrounding said winding leg, there being longitudinal space along the surface of said winding leg with in said cylinder, and windings surrounding said cylinder, said winding leg and cylinder being longitudinally inclined at a small angle with respect to said casing.

In witness whereof I have, hereunto set my hand this 22nd day of Oct, 1927.

VINCENT M. MONTSINGER. 

